論文 - 的場　正憲

La_0.7Pb_0.3Mn_1-zZn_yO₃における金属－非金属転移とZnによる磁気希釈

加納忠彦, 神原陽一，的場正憲

日本応用磁気学会誌 26   368-371 2002年04月

研究論文（学術雑誌）, 共著, 査読有り

新規な無機ハイブリッド型層状遷移金属硫化酸化物ペロブスカイト関連酸化物Sr₂Cu(Fe,Ga)O₃S および(Sr,La)₄Cu₂Mn₃O_7.5S₂の合成と評価

長沼 順子, 神原 陽一，的場 正憲

日本応用磁気学会誌 26   376-379 2002年04月

研究論文（学術雑誌）, 共著, 査読有り

層状Mn酸化硫化物Sr₂CuMnO₃Sの物性

神原 陽一, 岡田 悟志, 的場 正憲

日本応用磁気学会誌 26   372-375 2002年04月

研究論文（学術雑誌）, 共著, 査読有り

Magnetism of Novel Layered Cobalt Oxysulfide Sr₂Cu₂CoO₂S₂ with Strongly Correlated CoO₂ Square-Planes

Masanori Matoba, Tadamasa Takeuchi, Satoshi Okada, Yoichi Kamihara, Mitsuru Itoh, Kenji Ohoyama, and Yasuo Yamaguchi

Physica B 312-313   630-631 2002年03月

研究論文（学術雑誌）, 共著, 査読有り

　概要を見る

Magnetic and electronic nature have been investigated for the novel layered oxysulfide Sr_2_Cu_2_CoO_2_S_2_ (space group I/4mmm). Sr_2_Cu_2_CoO_2_S_2_ is the antiferromagnet with T_N_ (=200 K) determined by the measurements of neutron powder diffraction and magnetic susceptibility (χ). The dχ/dT shows a broad maximum indicative of two-dimensional antiferromagnetic nature, which is not originated from the (Cu^+^S)_2_ layers but the strongly correlated Co^2+^O_2_ square-planes revealed by the X-ray photoemission spectroscopy.

Magnetism of Novel Layered Cobalt Oxysulfide Sr₂Cu₂CoO₂S₂ in Strongly Correlated Electron Systems

Masanori Matoba, Kenji Ohoyama, and Yasuo Yamaguchi

Workshop on Studies of Structures in Magnetic Compounds by Neutron Diffraction Technique 2001 2001   11-13 2001年12月

研究論文（研究会，シンポジウム資料等）, 共著

　概要を見る

Magnetic nature has been investigated for the novel ayered oxysulfide Sr_2_Cu_2_CoO_2_S_2_ which crystallizes in an unusual intergrowth structure with alternating square-planar CoO_2_ planes and anti-PbO type Cu_2_S_2_ layers. Sr_2_Cu_2_CoO_2_S_2_ is the strongly correlated antiferromagnet with T_N_ (=200K) obtained from measurements of the magnetic contribution d(χT)/dT. Below 80K(=T_1_), the difference between ZFC and FC magnetic susceptibilities are observed, indicating that Sr_2_Cu_2_CoO_2_S_2_ exhibits a spin-glass-like (spin-frustrated) transition. Above 200K(=T_2_), magnetic susceptibility shows a broad maxium indicative of 2D antiferromagnetic coupling in the square-planar CoO_2_ planes. From the NPD HERMES experiment, below 200K(=T_2_) we have confirmed the occurrences of new additional reflection peaks, which can be indexed on the K_2_NiF_4_-type magnetic cell and can be therefore assigned to the square-planar CoO_2_ planes with antiferromagnetic ordering. The magnetic reflection peaks are clearly seen in the NPD pattern at 75K in the spin-glass-like (spin-frustrated) region, indicating a possibility that Sr_2_Cu_2_CoO_2_S_2_ is the unusual spin-glass-like material.

多元系層状磁性半導体Sr₂Cu₂Zn_1-xMn_xO₂S₂の物性

神原陽一, 岡田悟志, 的場正憲

日本応用磁気学会誌 25   739-742 2001年12月

研究論文（学術雑誌）, 共著, 査読有り

Neutron Powder Diffraction on Novel Layered Cobalt Oxysulfide Sr₂Cu₂CoO₂S₂ in Strongly Correlated Electron Systems

Masanori Matoba, Kenji Ohoyama, Shunji Soyano, Satoshi Fukumoto, and Yasuo Yamaguchi

Journal of the Physical Society of Japan 70   Suppl. A64-66 2001年07月

研究論文（学術雑誌）, 共著, 査読有り

Electronic structure of delafossite-type AgMO₂ (M=Fe, Co, Ni) studied by the cluster model analysis

Masanori Matoba, Hironobu Ueno, Hirotaka Okabe, and Mitsuru Itoh

Proceedings of the fourth Pacific Rim International Conferences on Advanced Materials and Processing (Hawaii, 2001)    2119-2120 2001年04月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り

Transport properties and electronic nature of delafossite-type PdCoO₂ and its related compounds

Hirotaka Okabe, Masanori Matoba, and Mitsuru Itoh

Proceedings of the fourth Pacific Rim International Conferences on Advanced Materials and Processing (Hawaii, 2001)    2117-2118 2001年04月

研究論文（研究会，シンポジウム資料等）, 共著, 査読有り

ペロブスカイト関連酸化物Sr₃(Ga_1-xMn_x)₂O₆ (0≦x≦0.2)の結晶構造と磁性

長沼順子, 的場正憲

日本応用磁気学会誌 25   719-722 2001年04月

研究論文（学術雑誌）, 共著, 査読有り

Cu-Substitution Effect on a Square-Planar CoO₂ Layer in a New Layered Transition-Metal Oxysulfide Sr₂Cu₂CoO₂S₂

Masanori Matoba, Satoshi Okada, Satoshi Fukumoto, Shunji Soyano, and Hijiri Kito

Japanese Journal of Applied Physics 39   498-500 2000年11月

研究論文（学術雑誌）, 共著, 査読有り

Optical study of the metal-nonmetal transition in Ni_1-δS

Hideaki Okamura, Jun Naitoh, Takao Nanba, Masanori Matoba, Masaya Nishioka, Shuichiro Anzai, Iwao Simomura, Kazutoshi Fukui, Hiroshi Miura, Hideyuki Nakagawa, Kazumichi Nakagawa, and Toyohiko Kinoshita

Solid State Communications 112   91-95 1999年09月

研究論文（学術雑誌）, 共著, 査読有り

　概要を見る

Optical reflectivity spectra of the hexagonal Ni_1-δ_S have been measured to study its electronic structures, in particular those associated with the metal–nonmetal transition in this compound. Samples with δ=0.002 and 0.02 are studied, which have transition temperatures T_t_ = 260 K and 150 K, respectively. Upon the transition, a pronounced dip appears in the infrared region of the reflectivity spectra. The optical conductivity spectra suggest that the nonmetallic phase is a carrier-doped semiconductor with an energy gap of 0.2–0.3 eV. The spectra also show that the gap becomes larger with decreasing temperature, and smaller with increasing . It is found that the overall spectrum in the nonmetallic phase can be explained in terms of a charge-transfer semiconductor, consistent with recent theoretical and photoemission studies of NiS.

Pressure Effect on the Curie Temperature of (Mn_1-zFe_z)₇Sn₄

Shuichiro Anzai, Seiji Fujii, Satoru Ohta, Hajime Yoshida, Takejiro Kaneko, Ryuichi Sugi, Takayuki Yoshida, Masanori Matoba, and Tomohiko Wada

The Review of High Pressure Science and Technology 7   547-549 1998年07月

研究論文（学術雑誌）, 共著, 査読有り

Magnetic susceptibility, thermoelectric power, electrical resistivity study of the nonmetal-metal transition in (Ni_1-xV_x)_0.98S

Masaya Nishioka, Teruki Motohashi, Masanori Matoba, Mitsuo Mikami, and Shuichiro Anzai

Physica B 237-238   151-153 1997年08月

研究論文（学術雑誌）, 共著, 査読有り

　概要を見る

Nonmetal-metal transition temperature Tt of (Ni1-xVx)0.98S increases up to x ~ 0.05, and then Tt decreases. The sign of thermoelectric power S below Tt changes from positive to negative with increasing x. These results indicate that the doped holes due to vacancies are compensated by doped electrons due to V and that the change of Tt concerns this compensation.

Long-Time Decay of Thermoremanent Magnetization through Stepwise Changes of the Reentrant Spin-Glass-Like State in the Ni₂In-Type Mn₇Sn₄

Yoshihiro Isogai, Takashi Kobayashi, Takayuki Yoshida, Shuichiro Anzai, and Masanori Matoba

Physica Status Solidi b 203   213-220 1997年08月

研究論文（学術雑誌）, 共著, 査読有り

　概要を見る

The zero-field-cooled magnetization at the magnetic field H = 300 Oe shows anomolous kinks at TA and TB (>TA far below the reentrant spin-glass-like transition temperature Tf (above which a long-range ferrimagnetic ordering is set up). The irreversibility between the zero-field-cooled and the field-cooled magnetizations, and the time decay of the thermoremanent magnetization (TRM) are observed below the ferrimagnetic Curie temperature TC. The decay feature can be described by Ogielski's power law TRM = At - whose exhibits peaks at TA, TB, Tf and TC. The peak of at TC can be fitted by the combination of Ising type and Ginzburg-Landau type expressions. Three stepwise changes of the spin-glass-like state below Tf and the feature of the coexistence of short-range spin-glass and long-range magnetic ordering components above Tf are discussed.

Single Hole Dynamics in the CuO₂ Plane at Half Filling

Johannes J. M. Pothuizen, Robert Eder, Nguyen T. Hien, Masanori Matoba, Alois A. Menovsky and George A. Sawatzky

Physical Review Letters 78   717-720 1997年01月

研究論文（学術雑誌）, 共著, 査読有り

　概要を見る

We present a k-dependent study of the single hole states in Sr_2_CuO_2_Cl_2_. We demonstrate that the controversial "1 eV peaks" in the high Tc's are quasi-particles derived from the same O 2p states as the Zhang-Rice (ZR) singlets, but of different symmetry and intensity in those regions of the Brillouin zone where the hybridization with the correlated Cu 3d states vanishes by symmetry. We use this new source of information to estimate the quasiparticle weight of the ZR singlets, discuss the quasiparticle line shape, and suggest a strong k dependence of the self-energy.

X-Ray Photoemission Spectroscopic Study on the Electronic States in the Mixed System between Charge-Transfer and Mott-Hubbard Type Metals : Co_0.91S and V_0.91S

Teruki Motohashi, Keiso Hayashi, Masanori Matoba, Shuichiro Anzai and Atsushi Fujimori

Journal of the Physical Society of Japan 65   1312-1316 1996年08月

研究論文（学術雑誌）, 共著, 査読有り

　概要を見る

In order to study the change of the electronic states from the charge-transfer(CT) type metal to the Mott-Hubbard (MH) one, X-ray photoemission spectra are measured on the NiAs-type (Co_1-x_V_x_)_0.91_S (x ≤ 0.50) and V_0.91_S. The asymmetry parameter α for S 2s and 2p core level spectra decrease with increasing x. This result indicates that the local density of states of S atoms at the Fermi level decreases as x increases; the system changes from the CT-type metal to the MH-one with x. The change in V 2p line shape with x suggests the possibility of the considerable hybridization between V 3d and S 3p in (Co_1-x_V_x_)_0.91_S at lower x region. This feature would be related to the appearance of the extra peak at binding energy E_B_ = 2-3 eV in the valence band X-ray photoemission spectra.

Metal-Nonmetal Transition in NiAs-Type Ni-Fe-S Compound : X-Ray Photoemission Spectroscopic Study

Masanori Matoba, Teruki Motohashi, Kunihiko Shimoda, Hikaru Tamura, Shuichiro Anzai and Atsushi Fujimori

Crystal Research and Technology 31   563-567 1996年08月

研究論文（学術雑誌）, 共著, 査読有り

X-Ray Photoemission Spectra of S 2s Core Level in the Charge-Transfer Type Mixed Metallic System (Co_1-xNi_x)_0.91S

Shuichiro Anzai, Teruki Motohashi, Keiso Hayashi, Masanori Matoba, and Atsushi Fujimori

Journal of the Physical Society of Japan 65   2724-2725 1996年08月

研究論文（学術雑誌）, 共著, 査読有り

Pressure Effect on the Magnetic Transition Temperatures of Ni₂In-Type (Mn_1-uCo_u)₇Sn₄

Takayuki Yoshida, Hajime Yoshida, Ryoichi Sugi, Yoshihiro Isogai, Naoya Tokiwa, Shuichiro Anzai, Masanori Matoba, Takejiro Kaneko, Shunya Abe, and Satoru Ohta

Journal of the Physical Society of Japan 65   1511-1512 1996年08月

研究論文（学術雑誌）, 共著, 査読有り